I've been everywhere down this road......and have tried so many different things over the years...
Few things...
If you go to a return system you had better make sure you are getting the fuel return to the fuel pump cup/siphon...or it will make things worse
The siphon will only work if there is a significant amount of fuel going through it...so if you increase your fuel requirements you will not get enough fuel transfer to get the fuel out of the passenger side.
If you put another pump in the passenger side...it will run dry a lot of the time on the street...not a good thing
So you need a switch...and the siphon intact if you plan on street driving the car
Basically after a lot of experimenting....I now have a transfer pump in both sides of the tank...and a large surge tank in the trunk with a Bosch 044 pump. With 500+ Hp in a REW swap I have never had fuel starvation this way....down till the transfer pumps are both sucking air
Overly complicated...yes...but the only thing I have found that works without a hiccup